Design and development of gasification processes in fluidised bed chemical reactor engineering
This thesis focuses on studying and investigation the effects of the hydrodynamic and operating parameters in the air-biomass gasification in a bubbling fluidised bed gasifier under low temperature (<800oC) conditions and evaluating the potential of the gasification of two solid biomass waste materials, Iraqi date palm wastes and sawdust pinewood. These parameters are air flowrate, particle size of the sand bed material, biomass particle size, static bed height, air equivalence ratio, bed temperature, number of holes in distributor plates and biomass fuel type.\ud A design study was conducted to provide preliminary data for designing and constructing a large lab-scale fluidised bed column, diameter D=8.3cm, for cold and hot fluidisation experiments. Cold fluidisation experiments were conducted to provide the fluidisation behaviour data for the sand, biomass and their mixture.\ud The design and cold fluidisation results have shown a compatible finding in the following: 1) the design parameter Umf has shown that, it increases as sand particle size increases. 2) It was not affected by static bed height. In addition, cold fluidisation results show that: sand has a high fluidisation quality compared to pure biomass and sand-biomass mixture and there is no effect of the bed static height on the Umf.\ud In general, the studied parameters on the air-biomass gasification performance have shown that: 1) air flowrate has a considerable effect, 2) as sand and biomass particle size increases a weakened gasification was achieved. 3) The static height effect has been observed due to the location of the biomass feeding position thereby affecting reactant residence time. 4) For equivalence ratio range (0.2-0.4) the lowest value provided optimum gas composition and LHV values, whereas the highest value ER= 0.43 provided highest (CCE), CGE) and (GY). 5) No significant effect was seen for bed temperature between 360 to 465oC. 6) A considerable effect has been shown for the distributor plate configuration.\ud Finally, the results has shown that SPWB has potential compared to IDPWB for energy generation. However, additional simulation, optimization and experimental studies on the bubbling fluidised biomass gasification for a broad range of operating and hydrodynamic parameters are hereby suggested.